The present invention relates to centrifugal abrasive throwing wheels sometimes referred to as blasting wheels or shotblast wheels, used to project particles against work pieces to subject the work to cleaning or abrading action.
In some shotblast wheel designs, blades, numbering between 4 to 12 per wheel, are held in place via mechanical means such as springs, pins, set screws or other mechanical retention devices. In these designs, the operator has minimal difficulty with the blades being held into position while they are being changed as the mechanical spring, pin or set screw holds each blade into position without concern of the blade falling back into the operator's fingers or hand during the blade changing procedure.
Many manufacturers have simplified the designs of centrifugal blast wheels to eliminate costly or difficult to use mechanical blade retention devices that oftentimes can fail or wear quickly. These centrifugal shotblast wheel designs require the operator to physically hold the blades into position with fingers extended into the center of the shot wheel unit. Holding multiple blades in place while trying to insert the last several blades is difficult and unsafe as blades can slip and cause injury to the operators' fingers or hands.
A typical centrifugal abrasive throwing wheel of this kind is shown in U.S. Pat. No. 5,476,412. Among the objects of the present invention is an improved method of installing Blades to a single plate or to a set of interconnected wheel plates for a centrifugal blasting wheel.
Airless centrifugal throwing wheels of the type described consist of a single or double wheel plate having a number of blades extending radially from the wheel plate(s) in equally circumferentially spaced apart relation, with a means of securing the blades between the wheel plate(s). In operation, the bladed wheel is rotated at high speed about a central axis and abrasive particulate material is fed onto the inner portions of the blade whereby the material is displaced by centrifugal force outwardly over the surface of the blades and projected at high velocity from the ends of the blades.
Blades of this type typically wear out under the abrading effects of the particles that are thrown. These abrasive particles move along the blades and gradually wear out portions of the throwing wheel as well as the blades themselves. Further when the blades become worn, the blades need to be removed and the equipment needs to be reset. In some applications, blade replacement can take place as often as everyday.